In a photolithographic technique for a manufacturing process of a semiconductor device, an optimum amount of shrink to keep a large DOF (Depth Of Focus) depends on the density of resist patterns obtained by patterning (the pitch of the patterns). For example, when the resist patterns are dense and the pitch thereof is quite small, the amount of shrink needs to be small or zero to keep the DOF. In contrast, when the resist patterns are rough and the pitch thereof is relatively large, it is preferable that the amount of shrink is larger to increase the DOF.
However, when dense patterns and rough patterns are both to be formed on the same semiconductor substrate, it is difficult to optimize the amount of shrink to keep the DOF.
To vary the amounts of shrink in the resist patterns, a polymer-blend DSA (Directed Self-Assembly) material is conceivably used. The polymer-blend DSA material is guided with resist patterns used as guide patterns, thereby forming finer patterns than the resist patterns. However, a solvent (butyl acetate, for example) of the polymer-blend DSA material has a property of dissolving a positive resist. Therefore, in a case where the resist patterns are formed of a positive resist, the solvent adversely dissolves the resist when the polymer-blend DSA material is used.